Here's the price tag for GOP health care plan: $600 billion

Speaker of the House Paul Ryan (R-WI) (3rd L) shares a laugh with Republican members of Congress after signing legislation to repeal the Affordable Care Act, also known as Obamacare, and to cut off federal funding of Planned Parenthood during an enrollment ceremony in the Rayburn Room at the U.S. Capitol in Washington, DC.

Repealing Obamacare may be politically popular, but the current proposals are going to be costly.

Republicans are moving ahead with campaign promises to repeal and replace the Affordable Care Act, known to most Americans as Obamacare.

Many of them have attacked the landmark law as too costly. But a back-of-the-envelope estimate finds that the replacement plan being floated would end up costing the federal government and additional $600 billion over 10 years.

The estimate comes from the congressional Joint Committee on Taxation, which made a preliminary estimate Tuesday of the cost of various provisions in the GOP repeal and replace plan, known officially as the American Health Care Act.

The plan fulfills a longstanding pledge to replace the Obama administration's landmark Affordable Care Act. Based on the initial estimates of the cost of the new law, the replacement doesn't appear to be affordable.

The estimate doesn't include the cost of repealing individual and employer mandates or the cost of tax credits proposed in the legislation, according to the Committee for a Responsible Federal Budget, a watchdog group.

"Without further information, it is impossible to know if these tax cuts will be fully paid for as part of the House plan, though it is clear that the inclusion of these tax cuts will leave less revenue available to finance any coverage provisions," the group said in a blog post.

The group also said the proposal would accelerate the looming insolvency of the Medicare hospital insurance trust fund.